Literary usage of Sour bread

Below you will find example usage of this term as found in modern and/or classical literature:

1.Lectures on the science of human life by Sylvester Graham (1854)"It is very strange,' said a lady to me one day at her dinner table, ' that some
folks always have sour bread, ar.J never know it. ..."

2.Sessional Papers by Ontario Legislative Assembly (1905)"The commonest disease or abnormal fermentation of bread is known as sour bread,
which means that the odor and flavor of the bread are sour to the senses of ..."

3.Baker's Bread by Paul Richards (1918)"During the hot season there is often serious trouble ahead for the baker in the
necessity to keep the doughs from getting too old and having sour bread. ..."

4.Bacteria, Yeasts, and Molds in the Home by Herbert William Conn (1912)"Recognizing that the cause of sour bread is due to the growth of bacteria, ...
The bacteria which produce sour bread do not, however,! come wholly from the ..."

5.Bacteria, Yeasts, and Molds in the Home by Herbert William Conn (1903)"Recognizing that the cause of sour bread is due to the growth of ... The bacteria
which produce sour bread do not, however, come wholly from the use of ..."